/Engine/Source/Editor/UnrealEd/Public/Toolkits/BaseToolkit.h
Creates the mode toolbar tab if needed
[TSharedRef](API\Runtime\Core\Templates\TSharedRef)< [SDockTab](API\Runtime\Slate\Widgets\Docking\SDockTab) > MakeModeToolbarTab ( const [FSpawnTabArgs](API\Runtime\Slate\Framework\Docking\FSpawnTabArgs) & Args )